Slime-pulp thickener



C. ALLEN.

SLIME PULP THICKENER.

APPLICATION FILED 0CT.10. 1918.

1,350,20 Patented Aug. 17,1920.

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In mentor Chqr'las'flllen To all whom it may concern:

, slime pulp in the PATENT OFFICE."

CHARLES ALLEN, or EL PASO,-TEXAS.

sLIME-PULP rHicKEivnR.

Specification of Letters Patent.

Original application filed June 9,1917, Serial No. 173,785. Divided andthis application filed October I v i 10, 1918. Serial No.257,624.

Be it known that I, CHARLES ALLEN, a citizen of the United States,residing at El Paso, in the county of El Paso and State of Texas, haveinvented provements in Slime-Pulp Thickeners, which. the following is aspecification.

This invention relates to a device for thickening slime or pulp,

closed in my co-pending application entitled, Slime pulp thickener,Serial Num ber 17 3,7 85, filed June 9, 1917, and of which ing of finelydivided solids in suspension, is

almost universally used in the treatment of ores by wet millingprocesses, and in its every application it is of prime importance thatthe degree of thickening be uniform; that is, that the discharge of thethickened slime be always of the same eners heretofore used depend uponthe volume of pulp fed to the cone or tank for regulation of the size ofthe discharge orifice. The results are very unsatisfactory, inasmuch astheproportion of liquids to solids in the material discharged varieswith the volume of slime pulp fed to the thickener.

In the present invention, the volume of thickener in no manner altersthe proportion of liquids to solids in the products discharged, withinthe limits of the capacity of the machine. The degree of thickening is'controlled, and forwhatever degree of thickening, the device isadjusted, that degree of thickening is automatically maintained.

In slime pulp, the finely divided solids move freely without thefluidity by friction among themselves.

Such a pulp has the properties of a liquid so long as the solids arekept in suspension.

hen the pulp iscomposed of water and solid particles of greaterspecificgravity,

than water, the specific gravity of the pulp "increases with allincreasesin the quantity compartment a liquid, and in the other a ofsolids in suspension in the pulp! This pulp may therefore ,be consideredas a liquid of greater density than water.- In my invention termed twocompartments having in one mixture of liquid and solidsor pulp. Thevariations inthel density of the pulp, due

new and useful Imand particularly pertains to a structure :similar tothat disdensity. T hickappreciably affecting overflows the rim of thetank. is provided to supply slime pulp to the I employ what :may becolumn of liquid, which column of liquid carries a float operativelyconnected to a valve at the bottom of the tank controlling the dischargeorifice. When the pulp attains a certain density the valve isautomatically opened to permit the discharge of the thickened pulpthrough the bottom ori- V lice, and when the density of the pulp fallsbelow a critical point, the valve is auto-- matically operated to closethe orifice. Hence the degree of thickening of the pulp dischargedthrough the automatically controlled orifice is practicallytlie sameunder all conditions or variations in the volume of slime pulp fed intothe tank. The

volume of thickened slime discharged through the'orifice may varyconsiderably, but the density of the thickened slime dis- 7 chargedremains practically constant. This is the reverse of the thickener-sordinarily used in which the volume of thickened slime dischargedremains constant while the densityof the discharge varies with thequantity fed'into the thickener.

The invention isillustrated by way of example in the accompanyingdrawing in which- Figure 1 is a view in vertical section Patented Aug.17, 19201 taken centrally of one form of the invention.

Fig. 2 is a view in vertical section taken centrally of another form ofthe invention, showing the actuating mechanism as disposed exteriorly ofthe tank.

Referring more particularly to the, drawing, the apparatus is shown ascomprising a tank 10 in the shape of an inverted cone having a dischargeorifice 11 at its bottom for carrying off the thickened product. Alaunder 12 is arranged around the top of the tank for carrying off clearliquid which A conduit center of the tank. The outlet 11. of the tank isindirectly controlled by a float 14 having variable buoyancy due to theapplication of adjustable weights 15. This float is provided withoperable connections 16 Y which extend downwardly and engage themechanismof a valve 17 controlling the discharge orifice 11. In thepresent instance the float is circular, being positioned within anannular chamber 18 which has outer and inner cencentrlcally spaced wallsforming considerably above that of the rim of the tank and furtherextends downwardly to a level below the rim of the tank. This chamber issupplied with clear water through an inlet supply pipe 19.-

In'Fig. 1 the float chamber is supplied with pipes which extenddownwardly through the conical top wall of the bell 21. he lower ends ofthese pipes terminate within an inverted conical receptacle '22 whichtelescopes into the bell 21, the

telescoping walls of the two members being spaced in relation to eachother. The conical end of the receptacle 22 projects downwardly into thebody of the pulp. hen the device is in operation the receptacle 22 aswell as the tubes 20 and the float chamber 18 are filled with clearwater. The overflow of water. from the receptacle 22 is prevented by anair cushion within the bell 21, the open bottom of which is sealed bythe pulp within the tank. To prepare for the'thickening operation, clearwater is admitted through the pipe 19 until the tank overflows, therebyfilling the float chamber to the level of the overflow lip of tank 10,tubes 20 and the receptacle 22. The float is adjusted and the slimeto'be thickened isturned into thetank through the conduit 13. As theslime thickens, its density increases, the level of the dense liquidpassing above the mouth of thebell 21.

-The air within the bell is then compressed and acts upon the body ofwater in the receptacle 22 to raise the level of the same within thefloat chamber, thus lifting the float and opening the discharge valve.

The air cushion within the bell prevents the comminglmg of the shinewith the clear water. This arrangement produces a structure not liableto readily wear or break and has proven to be execeedingly sensitive "tothe variations in the density of the slime. It will be understood thatwhen the density of the slime increases to sui'ficientlyaffect the clearwater within the float chamber and to raise its level, the float 14 willbe lifted to lower the valve member 17 and open the discharge orifice11.' If desired,- a water gage may be provided for'the bell and asimilar gage 24 provided for the receptacle, as shown in the drawing.

The form of the invention disclosed in Fi .2 embodies the use of a bell25 simisions as compared with the tank and its upper portion representsa conical shell of these members are located within ing contamination ofth clear water than those disclosed in Fig. 1 of the drawing or myco-pending' application abovementioned. It will be noted that the floatchamber- 18 is cylindrical and is disposed exteriorly of the tank, thereto receive a float 14. Both a supplemental tank 27. This tankcommunicates with the apex-of the bell 25 by means of a valved pipe 28which enters the lower elidof the tank and terminates beneath the openmouth of the float chamber 18. Communicating with the pipe 28 is a pipe29 which extends therefromand through an opening inthe top ofthesuppleinental tank- 27. This pipe is valved. and thereby insures thatwhen an air cushion is to be used in trai'ismitting the pressure of onecolumn of liquid to the other or where the air is dispensed with andwater transmission is used, thepipe 28 may be employed.v In operation ofthe device shown in Fig. 2, when it is "desired to employ the aircushion, the valve in the pipe 28 is opened and the valve in the pipe 29is closed. The float chamber and connected parts are then filled withclearwater through the supply pipe 19 until the tank10 overflows,whereupon the valve in the pipe 28 is closed and the ening then proceedsin themanner common to devices of this character.

\ 1 Variations in the density: of the" pulp above the bottom of the bell25 will be trans- .m-i-tted through the air column to the surface of thewater in the tank 27, thereby raising.

the level of the waterfin the-float chamber 18 and actuatingthedischarge valve. If no air cushion is to be used in the supplementarytank 27, the valve in the pipe29 is closed and. the valve in the pipe.28,'per-; lar'in construction and operation to that i shown in myco-pending application entitled manently opened. Any excess of airpress'urein the upper portionof the' t'ank 27 30. The-eifect of thedifference in the denwill be expelledv through a controllablewent sityof the two columns is thus transmitted f n to the water through pipe28,theibelln25 being in this instance entirely filled with water. 7

It will thus be seen that I make use of a hydrostatic balance betweentwo liquids of different densitiesto automatically control the dischargeof the thickened product. Among the advantages of this system may bementioned: First, that until the thickening hasprogressed to a certaindefinite density the orifice through which the thickened product isdischarged remains closed, but as soon as the thickening has reached thedesired point, the orifice is automatically opened. Second, if while thethickened product is being discharged, the degree of thickening fallsbelow the required consistency, the discharge valve is automaticallyclosed. Third, if the thickened product being discharged, increases ordecreases in consistency beyond what is desired, the discharge valve isautomatically moved to partial opening or closing position in order torestore the dischar ed product to the required consistency. ourth, therelative proportion of solids to water in the thickened productdischarged is under perfect control by simply altering the float line ofthe actuating float, and for whatever proportion of water to solids thefloat is weighted, that proportion is automatically main tained. Thismeans that the density of the thickened product discharged remainspractically the same under all working conditions. It will beunderstood, of course, that the actuating float may be so built as togive a definite degree of thickening without varying the buoyancythereof and hence the adjustable weights 15 may be omitted for a certainclass of thickening, but means whereby the float line of the actuatingfloat may be altered must be used in order to be able to adjust thethickener to various degrees of thickening.

Various changes in the construction and arrangement of the several partsherein shown and described may be employed with out departing from thespirit of my invention as disclosed inthe appended claims.

It is understood wherever the word water is used that I include in thatterm any other liquid or solution employed in practical millingoperations and with pulp to be subjected to my process.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. A slime pulp thickener comprising a tank having a discharge orificein the bottom thereof, a valve member normally closg said orifice, afloat chamber, a float supported upon the liquid therein, operatingmechanism between the valve and the float, means whereby variation inthe density of the pulp liquid within the float chamber to raise thewithin the tank will afiect the float and an air-cell between saidchamber and said means, whereby communication between the contents oftank and the contents of float chamber will be prevented.

2. A thickener for slime pulp comprising a tank having a controllabledischarge orifice in its bottom for the escape of settled material, achamber communicatin with said tank and adapted to receive a uid oflighter density than the pulp, a separating medium between the fluid andpulp capable of transmitting the pressure of the pulp to the fluidwhereby variation in the density of the pulp is registered by theraising and lowering of the fluid in the chamber, and meansactuated bythe rise and fall of the fluid for controlling the size of the dischargeorifice.

3. A thickener for slime pulp comprising a tank having a controllabledischarge orifice in its bottom for the escape of settled material, achamber communicating with said tank and adapted to receive a fluid oflighter density than the pulp, a cushion of air between the pulp in thetank and the fluid in said chamber adapted to transmit the pressure ofthe pulp to the fluid whereby variations in the density of the pulp arev the rise and wall of the water in the chamber, and a float carried bythe water in said chamber for controlling the size of the dischargeorifice.

5. A thickener for slime pulp comprising a tank having a controllabledischarge orifice in the bottom for the escape of settled material, achamber communicating with said tank and adapted to receive clear water,a separating medium between the water and pulp capable of transmittingthe pressure of the pulp to the Water whereby variation in the densityof the pulp is registered by the rise and fall of the water in thechamber, and means for adjusting the buoyancy of the float whereby thedensity of the discharged material is regulated.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

CHARLES ALL N Witnesses:

J. L. ELY,

EDMUND SHAW.

